Glucose-lipid ratio is a determinant of nitrogen balance during total parenteral nutrition in critically ill patients: a prospective, randomized, multicenter blind trial with an intention-to-treat analysis.

OBJECTIVE: Protein sparing, the major goal of nutritional support, may be affected by the glucose/lipid ratio. This study in critically ill patients compared the efficacy and tolerance of two isocaloric isonitrogenous total parenteral nutritions (TPN) having different glucose/lipid ratios. DESIGN: Multicentric prospective randomized study. PATIENTS: 47 patients with SAPS I score higher than 8 and requiring exclusive TPN. INTERVENTIONS: Patients received glucose/lipid ratios of 50/50 or 80/20. For 7 days all patients received 32 glucidolipidic kcal/kg and 0.27 g/kg nitrogen daily. All-in-one bags were prepared using industrial mixtures and a fat emulsion. MEASUREMENTS AND RESULTS: We determined TPN efficacy by nitrogen balance, urinary 3-methylhistidine/creatinine ratio, transthyretin and tolerance by glycemia, and liver enzymes. After controlling for five variables with significant effects, patients receiving the 50/50 ratio during TPN had significantly higher nitrogen balance than those receiving the 80/20 ratio. The daily difference in mean nitrogen sparing effect in favor of the latter group was 1.367 g (95% CI 0.0686-2.048). Glycemia on day 4 and gamma-glutamyltranspeptidase on day 8 were higher in group receiving the the 80/20 ratio. CONCLUSIONS: In critically ill patients TPN at a glucose/lipid ratio of 80/20 ratio induces a small nitrogen sparing effect compared to the ratio of 50/50, at the expense of poorer glycemic control. The clinical significance is unclear.

Liver function and plasma antioxidant status in intensive care unit patients requiring total parenteral nutrition: comparison of 2 fat emulsions.

BACKGROUND: Efficacy and safety of an alpha-tocopherol-enriched emulsion incorporating soybean, coconut, olive, and fish oils (SMOF) are compared in terms of biologic parameters to those of soybean oil-based emulsion (LIPOVEN). METHODS: Twenty stressed patients were randomly assigned in a double-blind study to receive at least a 5-day course of total parenteral nutrition. Plasma activities of liver enzymes, C-reactive protein, antioxidant capacity, alpha-tocopherol, retinol, and low density lipoprotein (LDL)-alpha-tocopherol levels were determined. LDL-lipid oxidation is measured after incubation of the LDL in the presence of a prooxidant. RESULTS: The plasma activities of liver enzymes and the phospholipids/apo A1 ratio were increased in both groups. However, in the SMOF group the increases were lower than in the LIPOVEN group and non-significant for the CRP plasma level and the alanineamino-transferase activity. Before parenteral nutrition, the plasma antioxidant status was markedly reduced in both groups. After parenteral nutrition discontinuation, the antioxidant capacity and the amount of LDL-derived oxidation by-products formed were comparable in both groups. There was a significant improvement in plasma lipophilic antioxidant vitamins and LDL-alpha-tocopherol levels only in the SMOF group. CONCLUSIONS: The lower increase of plasma liver enzymes and phospholipids/apo A1 ratio in the SMOF group suggest a better liver function than in the LIPOVEN group. This beneficial effect results in a higher liver mobilization and plasma levels of lipophilic antioxidants. They could, together with higher delivery of omega-3 fatty acids to peripheral tissues, contribute positively to survival rate of stressed patients.